Airbag Light and Other Gremlins - Help Needed!

[Naaaz]

Hey everyone, I'm the proud owner of a Lupo SDI Cambridge edition with an Open Air sunroof (though it doesn't work and leaks). I bought it for 400€ a few days ago. The rear lights were swapped for standard Lupo lights at some point in its life.

I'm dealing with a strange airbag issue that comes and goes as it pleases. I need to pass the technical inspection here in Belgium to register the car in my name, but the airbag has a mind of its own. It occasionally decides to act up and light up the dashboard. Below are the two codes I got when I scanned the car before buying it. After clearing them, the issue sometimes stays away for a while, but eventually, it comes back.

Additionally, the rear brakes are locked up. I'm considering doing a full refurbishment since cables, drums, and shoes are less than 100€ on Autodoc. Do you think it's worth repairing? Also, the alternator (I assume) gave out after I got home. The previous owner mentioned it was making noise, which it indeed was. It seemed like the brushes were the issue, but the car started fine despite the noise. Now, however, the alternator refuses to charge the battery, and the battery loses voltage when the car is on. Could it be the battery, or is it the alternator?

Overall, the car was well-loved at some point. It has four new tires, two new rear shocks, and the cambelt and water pump were replaced in January 2023. There's no rust at all, which is unusual, but the car hasn't been driven much since then. It starts up easily. Do you think it's worth investing in parts to keep it running, or should I cut my losses and scrap it? The car drives fine aside from these small issues. (I bought it to reduce some of the wear and tear on my GTI, which has seen 20,000 kilometers in 9 months. Fuel and money aren't really the issue, but I wanted to preserve the GTI's value by using the Lupo.)

[mk2]

Airbag issues are most commonly the little yellow plug on the back of the steering wheel or the clockspring unit (=the spiral wire assembly). You can also trick the airbag control module by placing a resistor across the two wires that lead to the airbag (and leave it disconnected!). I can't remember the value of the resistor, but I think it was 22ohms (I might be wrong- and VCDS will tell you if too high or too low again). It might be the airbag, but unlikely.

Locked up (stuck?) drums are a pain to release. If you take the wheel off, you might be able to get to the auto adjuster pin thing to back them off. @Rich What do you think? There might be nothing wrong- just rust making the shoes stick to the drums. But you'll need new drums and shoes. And bleed the brakes when you've finished... Not a big job. And not expensive either.

The alternator is probably the most difficult job on an SDI! It is easier to take the engine out... You have to remove it through the hole in the front, after releasing it. And releasing it is also tricky. You can see bolt details on the cambelt change how-to pics. The official way to get it out, it is to dismantle and remove the whole front of the car.

If the rest of the car is good, I would keep it. Things like alternators, brakes and bearings are common things.

[Naaaz]

I also suspected that the problem might be the clockspring since they tend to fail. Do you know if anyone has made a video or posted photos showing exactly what to do? I’ve done something similar on an old B6 I had, where I went from a dual ignitor to a single ignitor to retrofit a MK6 GTI wheel. That required soldering a resistor into the steering wheel control module, but it was easy because there were videos and pictures on forums. It seems like dealing with the airbag light will be straightforward.

The brakes weren’t completely locked up; I was able to drive 45 kilometers home, but I could tell the rear brakes were binding. Now they’re moving freely, but I haven’t had time to disassemble and inspect them yet. At least, for now, I don’t have a working handbrake, but the brakes are no longer stuck. I suspect it’s the same issue that newer VW Up models have, where rust and sediment build up inside the drums, causing them to stick. Refurbishing the rear brakes entirely would be best, and I agree with you that it’s not too expensive. I actually need to do it because they test the handbrake’s efficiency during the technical inspection, and it will fail if it doesn’t work.

Unfortunately, I’ve also noticed the infamous middle bolt, which is a pain to remove. I’m considering just changing the brushes to see if that solves the problem. If not, it’s another €100 part, but it’s a huge hassle. Fortunately, there are guides here that will hopefully help me tackle that more easily. I’ll post about it later when I eventually figure out what’s going on.

The car isn’t perfect by any means, but for a 20-year-old vehicle, it was a bargain by European standards. It drove itself home without overheating, though I’ve noticed that sometimes the oil light flashes for a split second at higher RPMs. It might just be my OCD, but I haven’t quite figured out if it’s a real issue or just me imagining things. There’s also the usual oil everywhere in the engine bay, so there are definitely leaks. I plan to get a more professional opinion from a mechanic friend and then decide what to do. I’ll keep you guys posted, and hopefully, someone can shed some light on the situation as I go along.

FYI: Just don't want it to be a money pit 🙃

[Rich]

I just bash drums with a hammer till enough crap falls out to make them spin nicely. 

[mk2]

Clock spring swap is really easy. Obvious once the steering wheel is off. See pics in the indicator and wiper switch how-to.

if you drove it home and the rear wheels turn ok, i know exactly what the problem is- The handbrake levers on the rear brake shoes each side sieze. The shoes will still be fine, and so are the drums I'd guess. A no cost fix. You need to takes the shoes off and clean them. Then you'll see a rivet which is used as a pivot for the handbrake lever- part of the shoe. Work it loose with some penetrating fluid until it is loose enough to flop about. Then clean again using some degreasing stuff and put a tiny drop of oil on that rivet/lever pivot. You'll have perfect brakes forever. I actually do it for brand new brake shoes.

I suggest everyone cleans out the inlet plenum and ram tubes. There's another how-to...  And block off EGR and divert the blow by gasses. The engine will run much cleaner. Also when you change the oil next, use CF4 grade oil (high detergent), as it keeps your diesel engine running way cleaner. I use 5W40 mannol extreme.

Service the gearbox- change the oil after a run - drain it straight after stopping to flush any particles out. Or you can be dangerous and do it with the wheels turning (you get everything out then!). 3L of synth 75W90 GL4/5.

Yeah, the alternator... i tried the brushes, but if you can measure any current coming out of the battery with the engine off (through the alternator cable connection), the one or more of the diodes inside has failed. That is what happened to me. I had to change it. Horrible, awful job. (They last about 200k km)

I'm very impressed with your English for a Belgian. Better than mine! 👍🏻😎

[Naaaz]

Long Overdue Update!

I finally found some time to start working on the car and wanted to update everyone. Here’s where things stand:

• Alternator: Turns out it was dead. The car actually broke down on my way to work (I drive buses). Luckily, one of the mechanics offered to take a look.

• Rear Brakes: Completely corroded, so I had to install a new rear brake kit.

• Openair Roof: It’s got a leak, who doesn’t?

• Blinkers/Headlight Switch: This was broken, so I replaced it today. However, I’ve now discovered that none of my high beams are working. The fuses look fine, so I'm a bit stumped on what to check next. The other light settings work, and the high-beam indicator on the dash lights up, so it’s a bit confusing.

• Clock Spring: This was also broken and tampered with before, so I replaced it. I haven’t connected it yet to see if it fixes the airbag light, but fingers crossed it does!

I haven’t done a full service yet since I’m trying to fix all these issues first before pouring more money into it. And thanks for the compliment on my English! I’m actually Portuguese, living and working in Belgium. Your English is great too the important thing is that we can communicate, no matter the language! 😄

On a positive note, the car drives amazingly. I can’t have as much fun in my Golf GTI, so I finally understand why people love these little cars. I imagine the 1.4 TDI with the PD engine would be an absolute blast!

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Question for the Community: Any suggestions on why my high beams aren’t working (even though the blue dash light comes on)? Any advice would be highly appreciated!